Method of feeding glass



E. C. STEWART METHOD OF FEEDING GLASS Fild Feb. 2, 1935 l Sept. 3, 1935.

.Patented Sept. 3,l 1935 BIETHOD OF FEEDING GLASS Edward C. Stewart, Washington, Pa., assignor to Tygart Valley Glass Company, Washington, Pa., a corporation of West Virginia Application February 2, 1933, Serial No. 654,794

3. Claims.

My invention relates to the feeding of molten glass in the form of mold charges, and more particularly to that type known as air feeders.

In air feeders, it has been common practice to mount a bell in a furnace boot, above the orifice in the bottom of the boot, and to effect pulsations of air within the bell, to produce pressure and suction lon the surface of the glass contained `within the bell, and thereby impart extrusive and retractive impulses to glass, and control movement thereof through the feeding orice.

In said type of feeder, adjustments to compensate for changes in temperature and viscosity of the glass, and for the purpose of varying the s1zes of mold charges, are effected by raising and lowering the bell, or by varying the pressure and suction impulses Within the bell, or both.

My invention has for one of its objects the provision of a means and method whereby little or no adjustment/orchange is necessary in the air supplied or in the positions of the bell.

Another,A object of my invention is to provide ,means for"varying the quantity of glass which may enter the bell during each cycle of a feed# such manner that desired sizes of mold ,charges produced,

can ,readily be notwithstanding changes `in temperature or viscosity of the glass, and can be produced with a minimum of cords resulting from a mixture of lcolder glass with glass of higher temperatures.

Some of the forms which my invention may take are shown in the accompanying drawing, wherein Figure 1 is a longitudinal sectional view through a portion of a glass furnace, andfeeding apparatus employed in connection therewith; Fig. 2 is a plan view thereof, on an enlarged scale, -and Fig. 3 is a cross-sectional view showing a modification of the structure of Fig. 1.

A glass furnace boot or forehearth is indicated by the numeral 5. An opening in the bottom ofl the boot contains a flow or orifice ring 6 that is detachably held in place by removable plates 1,

in any well-known manner.

Shears 8 are posito which charges of .glass dropped.

cut by the shears` are A metal shell or framework 9 extends around the forward end of the boot, and contains flanges thatl support rods IIJ, which at their upper ends carry a plate II. The positions of the nuts on the rods I are changed in order to effect vertical adjustment of the plate II and thereby vary the distance which the clay tube I2 extends into the body of molten glass I3. The clay tube constitutes in eect a portion of a bell, and is flanged or flared at its upper end so that it can be readily connected to the plate II, as by a collar I4. The connection between the collar I, the tube I2, and the plate I I is made air-tight.

A metal shell I5 is secured to the upper side of the plate II, and, together with the clay tube I2 forms in effect a bell. The upper end of the shell I5 is closed by a cover plate I6. The cover plate I6 has air-tight engagement with the upper end of the shell I5. The joints between the plates II and I6 and their associated members can be made air-tight, in any suitable manner, as by the use of iron cement which is applied in the form of paste, and becomes hardened. The metal members, and particularly the shell I5, are pref- .erably made of an alloy steel which has great heat resistance.

A stuinng box I 'I is mounted on the cover plate I6 and a lifting rod I8 extends through said stuifing box and the cover plate I6. Metal packing orthe like can be employed in the stufng box Il. The lower end of the lifting rod I8 is connected to a combined displacement member and valve I9 and can be lowered to completely close the orifice 6, or can be raised to permit glass to ow through said orice. The rate at which glass ows through the orice will depend somewhat upon the position of the member I9. Also, the position of the member I9 will determine the volume of molten glass contained within the bell when the glass in the bell is at the pool level. This is an'important feature of my invention, since when extrusive impulses are imparted to the surface of the glass in the bell, the amount of glass forced through the orifice 6 will depend largely upon the volume of glass within the bell.

The vertical positioning of the member I9 is effected by means of' a hand lever 20 acting through a link or pull rod 2l and a lever 22 that is pivotally supported on a bracket 23. 'I'he hand lever 29 can be maintained in any desired position by means of a pivoted pawl 24 carried thereby, that cooperates with a segmental rack 25 which is secured to the metal shell 9. It will be seen that if the handle 20 is moved downwardly from the position shown, the displacement member I9 will be raised further, so that a greater quantity of glass can enter thei'bell l2, because the tapered end of the member I9 will be raised further into the bell. A similar resultl would, of course, be -obtained if the tapered portion of the member I9 were entirely cut away. Therefore,

the glass.

By avoiding constant reciprocation of the member I9 in the manner followed in connection with some previous types of feeders, I avoid the tendency to form cords or ream in the glass.

Where there are wide changes in the sizes of thev glass charges which are to be supplied, or considerable change occurs in temperature of the molten glass, 'I will adjust the bell I2 vertically with respect to the orifice ID, as heretofore explained. V

Pulsations of air within the bell I2 are effected.

through a pipe 2I that communicates with the shell I5` and with a pump cylinder 28. .A piston 29 is reciprocated in the cylinder 28, Aby means of afluid motor 30 which has a piston 3I directly connected to the piston 29. The length of stroke of the piston 3|, and hence that of the piston 29 is controlled by an adjustable screw stop 32. Fluid is supplied to the cylinder 30 through pipes 33 and 34 from a suitable source, and control of pressure and exhaust through the pipes 33 and 34, to effectreciprocation of the piston 3I, can be effected in various well-known ways, in timed relation to movement ofthe shears 8 and the mold table. The reciprocati'on of the piston 29, of course, effects pulsationsin the air line 21|, and in the bell II to impart extrusive and retractive impulses to the glass.

Referring now to Fig. 3, I show a structure quite similar to that of Fig. 1, but wherein the metal shell I5- is eliminated, by reason of the fact that the clay tube or bell 36 has direct connection with a top plate 31. The bell 3B and the displacement member 38 are adjustable in the same manner as are the bell I2 and the member I9 of Fig. l.

A flow ring 4D is Adetachably maintained in place by a supporting plate or ring 4I, and is more readily removed than is the ring 6. Furthermore in 4changing the ow rings in Fig. 4,

the plunger 38 may be lowered to vshut oi ow through the bottom vof the boot, while such change is being made.

have their passageways of various sizes and of various contours. For example, on small ware, the bushing will have an .orice of smaller diameter than in the case of bushings which are employed in' the making of larger sizes of ware.

For certain ware, the orifice will be of circular form, while in the forming of charges for molds, which are o f oval or other non-circular form in cross section,' the orifice ofthe ow ring can be *correspondingly shaped in order that the contour of the mold charge may more closely conform to the contour of the mold, with consequent better distribution ofthe glass within the mold, when The orifice ring or bushings 6 and til-which are t employed inconnection with the apparatus may 5 the charge is expanded, thereby producing articles of more uniform wall thickness than in 'the case of non-circular articles formed fromg circular mold charges.

I claim as my inventiont- 1. The method of feeding charges of molten glass `through an orifice in the lower wall of a receptacle, which comprises mounting a bell above and in proximityto the orice and with its lower end` extending into the glass, vvarying the elective volume of glass within the bell at points below the normal glass level therein while thelbell is stationary, in accordanceswithw desired -changes in size of mold charges, and creating pneumatic impulses on the surface of the glass within the bell. 2. The method of feeding charges of molten glass through an orifice in the lower wall or a, receptacle, which comprises mounting a bell above and in proximity to the orifice and with its lower end extending into the glass, changing the vertical position of the bell andfindependently varying the elcctive volume of glass within the bell at points below the normal glass level therein, in accordance'with desired changes in size of mold charges, and creating pneumatic impulses on the'surface of the glass within the bell.

3.- The method o f feeding molten glass through an orifice which is below and communicates with 

